1. Related Applications
There is pending a Canadian patent application, Ser. No. 427,234, filed by the instant inventor, which includes a part of the subject matter hereof. There are no other related applications heretofore filed in this or any foreign country.
2. Field of Invention
My invention relates generally to cementuous, fiber containing building materials and a particular process for the formation and configuration thereof.
3. Background and Description of Prior Art
It has heretofore become a common practice in the building construction arts to form composite materials embodying combinations of various individual structural materials that have theretofore been commonly used, such as wood, brick, concrete, fiber board, insulating matter and the like, to attempt to create new materials having more desirable features and less undesirable features than the component elements individually. Increasing costs and greater environmental concerns have added impetus in the recent past to accelerate activity with such composite products and as a result, many and various of such products have become known.
Such materials in general have comprised a mixture of three essential classes of ingredients: firstly, some settable cementuous material, commonly a form of Portland cement or plaster; secondly, some relatively inert filler material that may aid in forming a cementuous matrix, such as sand or various silica-alumina mixtures of earth origin and; thirdly, a fibrous material of relatively low density and substantial insulative properties such as wood or other plant fiber, mineral fiber, synthetic fiber, or the like to lessen density and increase strength and insulative potential.
The prior art in dealing with such materials seems to have concentrated principally upon the relative quantities of the various components in a composite mixture and the addition of new and novel components to one or more of the classes of elements concerned. This art has become quite sophisticated with the passage of time and the use of such products in the building arts has increased somewhat proportionately with the sophistication of the art. Today there are known such products that are readily workable by ordinary hand and power tools and that may be mechanically fastened to other structural elements by nailing, stapling, screwing, adhering or the like, all in a fashion similar to wood. Many of these composite materials are quite durable and are not attacked by common microbal agents or insect pests that are often quite destructive of wood itself. Many such materials are more resistive to a physical or chemical attack, such as by freezing water, action of environmental bases and acids and the like, then ordinary concrete mixtures and have physical characteristics of strength, hardness and density that may be controllably varied over a wide range including at least the same characteristics of the component materials. In addition many such composite products are quite fire retardant or resistant and have substantial insulative values, both thermally and acoustically. Some of such materials, especially of more recent origin, have economic features approaching those of the substances from which they are formed and in some cases even surpassing them.
In distinguishment from this prior art, that has been concerned largely with the quantitative combination of ingredients in such composite construction materials, research had indicated that the manner and method of processing and admixing the various ingredients, both in subcombinations and totally, is at least as important as the quantitative definition of those ingredients, if not more so. My instant invention therefore differs from the aforesaid prior art not only in providing a new and different settable building composition, but also in providing a new and different process for the mixing and formation thereof.
For the siliceous component of my composition, I use diatomite or some similar material providing silica in a form with a very high ratio of surface area to volume. The prior art generally has used some form of crystaline quartz such as sand, particulated chert, or the like which does not have such a high surface area to volume ratio and is not therefore so potentially chemically reactive.
In the cementuous component of my material, I employ both Portland cement and calcium oxide, whereas this component in the prior art has generally comprised only one or the other of these ingredients. More importantly I process the calcium oxide with the siliceous component as a sub-mixture not only to admix the components but also to form or aid in forming a cementuous calcium silicate preliminarily to making a final mix of all ingredients. This process is aided by the particular nature of the siliceous material of my mixture. The prior art generally has not used a siliceous material having a very high ratio of surface area to volume and generally has not pre-processed that material with calcium oxide to allow a pre-formation of calcium silicate.
For the fiber component of my composition I use singulated wood fiber such as obtained from waste paper or as waste product from the paper industry, whereas the fiber component of most prior art compositions generally has been sawdust, shavings or similar agglomerated fiber often untreated to remove various substances deleterious to the cementuous reactions. These fibers have then been used as aggregate, such as sand and gravel are used in regular concrete. This created a combination of relatively weak wood fibers in a relatively strong, but rigid, dense and rock-like matrix which was inherently imbalanced. In my formulation such wood fibers can also be used, and for the common woods such as pine, fir, hemlock and spruce pre-treatment is not required. However, when agglomerated fibers are used, some of the singulated fiber should be also used. My cementuous paste is not so strong as Portland cement paste per se, but in my formulations this is not necessary, or even desirable. The resultant is lighter in weight, more insulative, more workable with cutting tools, and less expensive than that permitted by the prior art.
My process further differs from the prior art in that I form a first slurry of ground paper, quick lime (calcium oxide) and diatomite by boiling for two hours or longer in water or by bringing the mixture to the boiling point and then storing en masse in an insulated container for five days or longer. This slurry may be stored for extended periods after formation. I form a second dry concentrate by ball milling for thirty minutes or longer calcium sulfate, diatomite, and additives of iron oxide, calcium oxide, calcium chloride and other materials, as desired with sufficient water for hydration. This concentrate component may also be stored in an air-tight container for extended periods of time after formation.
I then admix appropriate quantities of the slurry and the concentrate with more diatomaceous earth, Portland cement, fiber, other additives and water, if required, to form a thick paste. The paste is then molded and pressed to remove a substantial portion of its contained water.
Prior art processes generally have not allowed pressing of the final composition as that pressing would remove too much of the cementuous component. My composition allows pressing because of its high fiber content and because of the singulated nature of the fiber which allows that fiber to act as a filter to retain the cementuous component within the composition. After pressing, my composition is a partially set, molded material that can be immediately unmolded and stacked on pallets without slumping. Prior art compositions generally are not self-supporting for substantial periods of time after formation which adversely affects the economics of their processing. My material after unmolding may be air cured or preferably kilned at approximately 65.5 degrees C. for 12 hours or longer until a more permanent set of substantial strength is obtained.
None of the construction compositions of the prior art are known to be produced by a process such as that herein disclosed. My product similarly differs from the prior art, either singularly or in any combination, by reason of the different materials comprising its components and also by reason of the nature of the ultimate product produced therefrom, all as hereinafter more particularly described and claimed.